How to change the scrolling position? - javascript

I want to have my content fade in on scrolling, but it reacts to late. How can I change it, to have my content fade in earlier?
I am very new to javascript and couldn't get it worked yet.
$(window).on("load",function() {
$(window).scroll(function() {
var windowBottom = $(this).scrollTop() + $(this).innerHeight();
$(".fade").each(function() {
/* Check the location of each desired element */
var objectBottom = $(this).offset().top + $(this).outerHeight();
/* If the element is completely within bounds of the window, fade it in */
if (objectBottom < windowBottom) { //object comes into view (scrolling down)
if ($(this).css("opacity")==0) {$(this).fadeTo(500,1);}
} else { //object goes out of view (scrolling up)
if ($(this).css("opacity")==1) {$(this).fadeTo(500,0);}
}
});
}).scroll(); //invoke scroll-handler on page-load
});
Right now the content space is blank until I scroll to the bottom. I need to have my content fade in when it is on like half of the page or earlier. Maybe changeable to any height with percent or pixel?

The shared portion of code fades element in once they are completely in the viewport (= when bottom of the elements is in the window).
How about fading elements in as soon as their tops get in the viewport?
Fade out logic should remain as is: elements should be faded out once their bottom get out of the viewport.
Adapted code:
$(window).on("load",function() {
$(window).scroll(function() {
var windowBottom = $(this).scrollTop() + $(this).innerHeight();
$(".fade").each(function() {
/* Check the location of each desired element */
var objectTop = $(this).offset().top
, objectBottom = $(this).offset().top + $(this).outerHeight();
/* If the element's top gets within bounds of the window, fade it in */
if (objectTop < windowBottom) { //object comes into view (scrolling down)
if ($(this).css("opacity")==0) {$(this).fadeTo(500,1);}
} else if (objectBottom >= windowBottom){ //object goes out of view (scrolling up)
if ($(this).css("opacity")==1) {$(this).fadeTo(500,0);}
}
});
}).scroll(); //invoke scroll-handler on page-load
});

Related

change div height when scrolling down

I have div element that contain google map. The div is on the half of the page, and it's start from the middle (more or less).
Is it possible that the height of it will be expand when user scroll down ( and shrink when scroll up) ?
I have some script that do it, but it's not so friendly.
and the current script is:
// change map size when scroll down
$(window).scroll(function() {
var scroll = $(window).scrollTop();
if (scroll >= 450) {
$("#map-warp").addClass("change-map-canvas"); // removed the . from class
$("#map-warp").css("margin-top", "40px"); ; // change margin from top for close infoWindow button
} else {
$("#map-warp").removeClass("change-map-canvas"); // removed the . from class
$("#map-warp").css("margin-top", "10px"); ;
}
});
Try this here:
$(window).scroll(function() {
var scroll = $(window).scrollTop();
var topMargin = 10 - $(window).scrollTop();
if (scroll >= 570) {
$("#map-warp").addClass("change-map-canvas");
$("#map-warp").css("margin-top", "40px");
} else {
$("#map-warp").removeClass("change-map-canvas");
$("#map-warp").css("margin-top", topMargin+"px");
}
});
Until the scroll reaches 570, the map will always stay like in the beginning. After that it will smoothly follow the scroll.

mouse over event within certain window y range

I am working on a project that requires the full length logo shrink to short initial in 2 situations:
A) when page scroll down past 300px.
and
B) if page hasn't scroll past 300px (meaning full length logo still showing), shrink the full length logo to initial to accommodate pulldown menu when mouse over the top menu items.
Here is the code I tried:
it is working but when page scroll past 300px the mouse out should not happen. It should keep the logo as the smaller initial format. Right now the mouse out will happen no matter the page is scroll past 300px or not.
/* shrink logo when page scroll past 300px by adding .smaller class to #logo. */
window.onscroll = function() {myFunction()};
function myFunction() {
if (document.body.scrollTop > 300 || document.documentElement.scrollTop > 300) {
document.getElementById("logo").className = "smaller";
} else {
document.getElementById("logo").className = "";
}
}
/* shrink logo when mouse over top menu items (.showlp) only if page has NOT scroll past 300px */
$(document).ready(function(){
$(".showlp").mouseover(function(){
if (document.body.scrollTop < 300 || document.documentElement.scrollTop < 300) {
document.getElementById("logo").className = "smaller";
}
})
$(".showlp").mouseout(function(){
if (document.body.scrollTop < 300 || document.documentElement.scrollTop < 300) {
document.getElementById("logo").className = "";
}
})
});
Any help is appreciated.
Pass parameters via data attribute in the body tag and access that value via you javascript code.
Eg.
then on your javascript
var ctrl=
$("body").attr("
data-var");
then on your window scroll function set the attribute value to 1, aand listen to it on your mouse over function to know when to
add the functionality.
Eg.
Function
myfunction(){
if(document.bo
dy.scrollTop>3
00){
// swap urclass
// then do
$("body").attr("
data-var", 1);
}
then on your mouse over function do:
$(document).re
ady(function(){
$(".showIp").mo
usover(functio
n(){
var ctrl=
$("body").attr("
data-var");
if(ctrl==1){
//swap class
}
else{
//keep swap
}
});
});

jQuery scroll fade-in crash

This code works well, but when I scroll up and down after 4-5 times it crashes and all the elements disappear. Why does this happen and how do I fix it?
$(window).on("load",function() {
$(window).scroll(function() {
var winheight = $(window).innerHeight();
$(".fade").each(function() {
/* Check the location of each desired element */
var objectBottom = $(this).offset().top + $(this).outerHeight();
var windowBottom = $(window).scrollTop() + $(window).innerHeight();
/* If the element is completely within bounds of the window, fade it in */
if ( windowBottom > (objectBottom - (winheight*0.65))) { //object comes into view (scrolling down)
if ($(this).css("opacity")==0) {$(this).fadeTo(500,1);}
} else { //object goes out of view (scrolling up)
if ($(this).css("opacity")==1) {$(this).fadeTo(500,0);}
}
});
}); $(window).scroll(); //invoke scroll-handler on page-load
});
Ok, I supposed that your html is something like this: https://jsfiddle.net/szdwwdac/
Sometimes, if you are scrolling fast up and down, when the element is fading out, your if doesn't work well.
if ( windowBottom >= (objectBottom - (winheight*0.65))) {
if ($(this).css("opacity")==0) {$(this).fadeTo(300,1);}
} else { //object goes out of view (scrolling up)
if ($(this).css("opacity")==1) {$(this).fadeTo(300,0);}
}
It's because of the 500ms of animation.
One of the solutions can be the eneble/disable for 500ms of the scroll page.
You can check this solution: How to disable scrolling temporarily?
EDIT
Another solution can be: add a class "fading" when you are inside your if. Then, in the if, eval if the element hasClass "fading". If not, you can go inside and make the animation.

Parallax scrolling opacity issue

I am coding my page so that the content fades in and out as you scroll.
when you scroll away from the "trilogy" section, then scroll back up, it is not 100% opacity when at the top again.
Also the content fades out half way the trilogy section, then fades back in again. I need the content when at the top (minus the green header area) to be 100% opacity when in view.
Code:
$(document).ready(function() {
$(window).bind('scroll', function(e) {
setParalaxContent();
});
function setParalaxContent() {
var trilogy = {
scrollTop: $(window).scrollTop(),
windowHeight: $(window).height(),
contentTop: $('.trilogy2').position().top,
contentHeight:2200
};
// determine scrollTop's bounds where content enters & exits the window
trilogy.lowerBound = trilogy.contentTop - trilogy.windowHeight;
trilogy.upperBound = trilogy.contentTop + trilogy.contentHeight;
// determine scrollTop's position percentage (x2) in relation to bounds
trilogy.percent = (trilogy.scrollTop - trilogy.lowerBound) / (trilogy.upperBound - trilogy.lowerBound) * 2;
}
$('.trilogy2').animate({
opacity: 1 - Math.abs(trilogy.percent - 1)
}, 1);
Please see full code at:
http://jsfiddle.net/warrior_76/pnr4fdyg/

Move div with window scroll not consistent

I need my sidebar to scroll up and down with the window but stop when the div is at its top or bottom. The code below works when the page is first loaded and scrolled down or when the page is scrolled up slowly, but when the page is scrolled to the very bottom of the sidebar div, the page has to reach the top (and then some) in order to trigger that margin change.
Is there some other trigger I should be looking for besides just on scroll? How can I adjust this code to properly adjust the div?
$(window).on("load scroll", function() {
var scrollYpos = $(document).scrollTop();
var sidebarinfo = $("#sidebar").offset().top + $("#sidebar").height();
var windowinfo = $(window).height() + $(window).scrollTop();
if ((windowinfo)<(sidebarinfo)){
$('#sidebar').css('margin-top', -scrollYpos);
}
});
The sidebar div is fixed position. If I use absolute position, the div scrolls fine, but it doesn't stop when the bottom of the div has been reached - it just continues to scroll with the window.
I've fixed the main part of the problem with this code.
$(window).on("load scroll", function() {
var sidebarinfo = $("#sidebar").scrollTop() + $("#sidebar").height();
var windowinfo = $(window).innerHeight() + $(window).scrollTop();
if ((windowinfo)<(sidebarinfo)){
$('#sidebar').css('top', -($(window).scrollTop()));
}
});
The only problem is on page load, the sidebar gets stuck in the wrong position until it is scrolled all the way up (and more).
I actually figured out that I needed to adjust a few things and add an else clause:
$(window).on("scroll", function() {
var scrollmargin = $(window).scrollTop() - $("#sidebar").outerHeight();
var sidebarinfo = $("#sidebar").scrollTop() + $("#sidebar").outerHeight();
var windowinfo = $(window).innerHeight() + $(window).scrollTop();
console.log($(window).scrollTop());
if ((windowinfo)<(sidebarinfo)){
$('#sidebar').css('top', (sidebarinfo + scrollmargin)*-1);
}
else {
var margintop = $(window).innerHeight() - $("#sidebar").outerHeight();
$('#sidebar').css('top', margintop);
}
});

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